Chlorofluorocarbons (i.e., compounds containing only carbon, fluorine and chlorine) have been used for many years as refrigerants, heat transfer media, foam expansion agents, aerosol propellants, solvents and power cycle working fluids. However, there has been recent concern that chlorofluorocarbons might be detrimental to the Earth's ozone layer. Consequently, there is a worldwide effort to find alternative compounds which contain fewer chlorine substituents, preferably compounds containing no chlorine. Pentafluorodimethyl ether has been proposed as a replacement for some CFCs (see e.g., PCT Publication No. WO 94/02564). Thus, there is an interest in pentafluorodimethyl ether, and a need for an efficent process for its production.